On Sat, Apr 7, 2012 at 5:21 PM, Ben Pfaff <blp@cs.stanford.edu> wrote:> "H. Peter Anvin" <hpa@zytor.com> writes:>>> On 04/06/2012 02:54 AM, Alexey Dobriyan wrote:>>>>>> Without proc knowledge about fdtable is gathered linearly and still unreliable.>>> With nextfd(2), even procful environments could lose several failure branches.>>> And they can keep old dumb fd++ or smart /proc/self/fd loops for a change.>>>>>>> Incidentally, if we were to create a system call for this -- which I so>> far see no reason for -- I would make it return a select-style bitmask>> of file descriptors in use, not a "next fd" which would require a system>> call per iteration.>> It's already possible to do something a little like that with the> existing "poll" system call:>> #include <stdio.h>> #include <sys/poll.h>>> int> main(void)> {> enum { N_FDS = 1024 };> struct pollfd fds[N_FDS];